The Medicare agency is warning managed care plans that it will penalize them if they discriminate against beneficiaries based on their health conditions when the agency starts next year to allow plans to offer different benefits, premiums, and coinsurance to some enrollees.

The Centers for Medicare & Medicaid Services said it will watch for plans targeting additional supplemental benefits and discounted cost sharing for beneficiaries with some diseases, while excluding those with higher-cost conditions, the agency said in an April...